(791d) Electrical Percolation in Nanostructured Polymeric Networks

Uniform dispersion of single walled carbon nanotubes (SWNT) in an epoxy was achieved by a streamlined mechano-chemical processing method. SWNT-epoxy composites were synthesized using a room temperature ionic liquid (RTIL) with an imidazolium cation and dicyanamide anion. This ionic liquid behaves as a dispersant for SWNTs and initiator for epoxy polymerization, and the material was processed using three roll milling. The SWNT dispersion of the resultant composite was evaluated by scanning electron microscopy and electrical conductivity measurements in conjunction with percolation theory. By adjusting processing parameters an ultralow critical percolation of 4.29x10^-5 volume fraction SWNTs was achieved. This percolation threshold is among the best presented in literature, with the benefit of streamlined processing methods and evidence of intact high aspect ratio tubes in the final composite. Mechanical property improvements of a well dispersed SWNT-epoxy network were evaluated and compared with a multiscale Monte Carlo finite element method (MCFEM) for determining mechanical properties of polymer nanocomposites. MCFEM parameters were derived from materials used in experimental work and scanning electron micrographs, resulting in a realistic Young’s modulus prediction which was in agreement with experimental findings.